Cutting Sitting Time Could Extend Life

Limiting the time we spend sitting to just three hours a day could add an extra two years to our life expectancy, scientists calculate.

Similarly, if we cut daily TV viewing down to two hours we could add on 1.4 years, they say in a report for the online journal BMJ Open. But experts say the US estimates, which are based on five separate population studies, are too unreliable to predict personal risk. Plus the targets are unfeasible.

Adults are advised to do at least two-and-a-half hours of moderate-intensity aerobic activity such as cycling or fast walking every week, as well as a couple of sessions of muscle-strengthening exercises like lifting weights or digging in the garden. But even if you do this recommended amount, you may still be sedentary – for example, if you work in an office you may spend most of your working day sitting.

A growing body of evidence suggests the more time we spend sitting, the less healthy we may be. Several studies have linked sitting and television viewing to conditions like diabetes and heart disease as well as an increased overall risk of death from any cause. But finding a link is not the same as proving one thing actually causes the other.

Dr Peter Katzmarzyk and Prof I-Min Lee who carried out the review stress that their estimates are theoretical. But given that the adults in their research spent, on average, half of their days sitting “engaged in sedentary pursuits”, the findings could provide an important public health warning.

On the average, how many hours do you spend sitting in a day? Do you agree with this study that sitting all day makes you unhealthy?